1. Field of the Invention
The present invention relates to fish tags and, more particularly, to fish tags having an invasive cellularly adhering point of attachment.
2. Description of the Prior Art
Fishery scientists have been searching for the ideal fish mark or tag since 1873 when Atlantic salmon were tagged in the Penobscot River, Me., and later recovered in fair numbers. The ability to account for the presence for a particular fish or group of fish in time and space furnishes a basic tool for fishery resource management. Fish tags and marks can be divided generally into categories where the fish is mutilated in some manner, as by removing a fin or part of the maxillary bone, by tagging, which involves the insertion, attachment or injection of a foreign object of substance or natural tags such as parasites or bacterial fauna and kemoprints. Color marks and radioactive tags may be injected or the fish may be emersed in colored or radioactive solutions.
An ideal mark or tag has certain characteristics, which characteristics include: remain unaltered during the lifetime of the fish; have no effect on fish behavior or make the fish more available to predators; not tangle with weeds or nets; be inexpensive and easily obtained; fit any size fish with little alteration; be easy to apply without anesthetic and with little or no stress to the fish; permit enough variation to at least separate groups; create no health hazard; cause no harm to fish as food or to aesthetics; be easy to detect in the field by untrained individuals; cause no confusion in reporting; and remain unaffected by preservation.
In selecting a particular mark or tag, several factors must be considered to assure the success of any large scale tagging program. These factors include: length of time the mark is to remain on the fish; personnel available for applying the mark; species of fish; methods of capture and handling; and interstate or international programs affecting the fish to be marked or tagged.
A number of tags have been developed over the years. Several of these will be described below but it is to be understood that variants of each tag identified also exist. The Archer tag consists of a single plate attached by two wires which wires pierce the tissues and are then twisted or clenched. The Atkins tag consists of a bead or flat plate attached by thread or wire that pierces the tissues to form a loop. The bachelor-button tag consists of two plates held together rigidly by a shaft that pierces the tissues. The barbed tag consists of a straight shaft with or without an attached plate that is pushed into the tissues and that depends for holding wholely upon one or more barbs. The body cavity tag may be any material inserted loosely into the body cavity. The collar tag is a ring of any material attached wholely by encirclement without piercing any tissues. The hook tag is a shaft piercing the tissues and held by the curve of the shaft and one or more barbs. The hydrostatic tag is a tag hollowed so that it's specific gravity is very slightly less than that of water and is attached by a wire piercing the tissues. The internal anchor tag consists of a flexible chain or thread that pierces the body wall and is held in place by being attached to material inside the body cavity. The jaw tag is attached by encirclement of any of the bones of the jaw. The Petersen tag consists of two plates or discs attached loosely together by a wire or a pin that pierces the tissues. The strap tag is a flat metal strip in which one pointed end pierces the tissues and is clenched through a hole in the other end. A modified Carlin tag consists of a plastic pennant attached by a wire link to a double wire through the fish's back. The spaghetti tag is a loop of vinyl tubing attached to the back of the fish. Other means for marking fish include biotelemetry, color marking, radioactive marking, tattooing, branding, fluorescent pigment, tetracycline antibiotics and mutilation.
Generally, mechanically attached invasive tags are relatively easy and quick to apply but generally work loose. Such loss of the tags may be exacerbated through rejection by the flesh in relative contact with the tag. Those tags which are locked about a bone have greater longevity but the loop used is not attachable quickly and easily and it tends to become caught upon weeds, rocks, sticks and similar articles. Deliberate mutilation is not readily recognizable by the general public and has limited value. Marking (such as color, radioactivity, tetracycline) of the fish is generally too sophisticated, if effective, to be recognizable by the general public. For any such marking which does not identify the marking agency, reporting by the general public is generally unavailable.